The term “carrier pipe” describes a pipe used to transport fluids from one place to another. Carrier pipes can be used to transport a wide range of fluids, including petroleum products, chemicals, gases, water, and waste streams. Carrier pipes are typically, but not always, installed underground (under roads, railways, canals, rivers, etc.) where they can be exposed to dynamic and static loads, corrosive elements, vibrations, and other stressful forces. To prevent these stressful forces from damaging carrier pipes and, thus, to prolong the serviceability of carrier pipes, carrier pipes are often installed inside a casing pipe.
A casing pipe is a pipe in which a carrier pipe or a plurality of carrier pipes is/are installed. A casing pipe typically has an inner diameter long enough to create an annulus between the casing pipe and the carrier pipe or plurality of carrier pipes installed inside the casing pipe.
When a carrier pipe or plurality of carrier pipes is/are installed inside a casing pipe, it is often desirable to maintain the carrier pipe or plurality of carrier pipes at a desired position or alignment along the length of the casing pipe, or in the case of gravity flow lines, to maintain the carrier pipe at a desired grade or position along the length of the casing pipe. Casing spacers have been invented for this purpose. In addition, casing spacers serve the purpose of electrically isolating the carrier pipe from the casing pipe to eliminate galvanic corrosion between two dissimilar metals. Where a plurality of carrier pipes is installed inside the casing pipe, casing spacers serve the purpose of electrically isolating each carrier pipe from the other carrier pipes and the casing pipe. Different types of casing spacers are equipped to support a single carrier pipe or a plurality of carrier pipes.
In the case of a single carrier pipe, a conventional casing spacer typically includes a band that is secured around the carrier pipe. Attached to the band is a plurality of risers or supports that extend outward from the surface of the band. In the case of a plurality of carrier pipes, a conventional casing spacer is a sheet of material having multiple holes and cutouts in which the plurality of carrier pipes are placed. In all cases, the casing spacers are typically placed at desired locations along the length of the carrier pipe or plurality of carrier pipes to support the carrier pipe or plurality of carrier pipes along the length of the casing pipe.
In a typical installation of a carrier pipe or a plurality of carrier pipes into a casing pipe, the string of carrier pipes or plurality of carrier pipes are either pushed or pulled into the casing pipe. During the installation process, the string of carrier pipes or plurality of carrier pipes may tend to twist or corkscrew as it is being pushed or pulled into the casing pipe. There are devices that have been designed to prevent or limit the twisting or corkscrewing of the string of carrier pipes or plurality of carrier pipes, but as discussed in further detail below, the present invention for preventing or limiting the twisting or corkscrewing effect is a component of the casing spacer.